Independent examination of the factor structure of the cognitive assessment system (CAS): Further evidence challenging the construct validity of the CAS

This study is the first to examine independently the factor structure of th e Cognitive Assessment System (CAS; Naglieri & Das, 1997) with a primary da taset not collected by its authors. Participants were 155 students (59 boys , 96 girls), ages 8 to 11 (M = 9.81 years, SD = 0.88), in Grades 3 to 6. Co nfirmatory factor analysis (CFA) was used to compare the fit provided by th e planning, attention, and simultaneous-successive (PASS) model, the theore tical model underlying the GAS, with alternative models of cognitive abilit y suggested by previous research. Results of this study indicated that the PASS model did not provide a better fit to the data than did alternative hi erarchical and nonhierarchical models. Not only were the Planning and Atten tion factors of the PASS model virtually indistinguishable (r = .88), but t hey demonstrated inadequate specificity for meaningful interpretation. The model reflecting the actual hierarchical structure of the CAS was found to fit the data no better than alternative models based on different theoretic al orientations. Of the hierarchical models examined in this study, the bes t fitting was a hierarchical (PA)SS model with one second-order general fac tor, psychometric g, and three first-order factors reflecting Fluid Intelli gence/Visual Processing (Simultaneous), Memory Span (Successive), and Proce ssing Speed (Planning/Attention). In sum, results of this study support Kra nzler and Keith's (1999) conclusion that the CAS lacks structural fidelity, which means that the CAS does not measure what its authors intended it to measure. Results of this study, therefore, provide further evidence challen ging the construct validity of the GAS.